<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			body{
				background: #222;
			}
			.box{
				width: 0;
				border-left: 50px solid #222;
				border-top: 100px solid red;
				border-right: 50px solid  #222;
			}
		</style>
	</head>
	<body>
		<div class="box"></div>
	</body>
</html>
